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1/*
2 * Copyright (C) 1995-2004 Russell King
3 *
4 * Delay routines, using a pre-computed "loops_per_second" value.
5 */
6#ifndef __ASM_ARM_DELAY_H
7#define __ASM_ARM_DELAY_H
8
9extern void __delay(int loops);
10
11/*
12 * This function intentionally does not exist; if you see references to
13 * it, it means that you're calling udelay() with an out of range value.
14 *
15 * With currently imposed limits, this means that we support a max delay
16 * of 2000us and 671 bogomips
17 */
18extern void __bad_udelay(void);
19
20/*
21 * division by multiplication: you don't have to worry about
22 * loss of precision.
23 *
24 * Use only for very small delays ( < 1 msec). Should probably use a
25 * lookup table, really, as the multiplications take much too long with
26 * short delays. This is a "reasonable" implementation, though (and the
27 * first constant multiplications gets optimized away if the delay is
28 * a constant)
29 */
30extern void __udelay(unsigned long usecs);
31extern void __const_udelay(unsigned long);
32
33#define MAX_UDELAY_MS 2
34
35#define udelay(n) \
36 (__builtin_constant_p(n) ? \
37 ((n) > (MAX_UDELAY_MS * 1000) ? __bad_udelay() : \
38 __const_udelay((n) * 0x68dbul)) : \
39 __udelay(n))
40
41#endif /* defined(_ARM_DELAY_H) */
42